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' W. W. MINER;

' Annealing Nails. No. 230,644. Patented Aug. 3,1880.

wifr a ssesr I I ja fdr' d a r W UNITED STATES PATENT OFFICE.

WILLIAM W. MINER, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO GLOBE NAIL COMPANY, OF SAME PLACE.

ANNEALING NAILS.

SPECIFICATION forming part of Letters Patent No. 230,644, dated August 3, 1880.

Application filed May 17, 1880.

To all whom it may concern:

Be it known that I, WILLIAM W. MINER, of

Boston, county of Suffolk, State of Massachusetts, have invented an Improvement in Annealing Animal-Shoe Nails, of which the following description, in connection with the accompanying drawings, is a specification.

' This invention relates to an improved in ethod of annealing animal-shoe nails, and also to apparatus therefor, as hereinafter described.

A very large portion of the animal-shoe nails now in market are made from blanks cut from hot-rolled plates usually ribbed to form thick portions for the heads, and these blanks are subsequently cold rolled or drawn to form nails of the proper taper and to stiffen their shanks.

The metal usually employed is that known as homogeneous, it having little or no grain.

I have discovered that an animal-shoe nail made from a blank punched cold from a rolled plate of homogeneous or steelified iron, or a hot-forged blank, if treated or annealed as hereinafter described, may be made to stand a greater amount of strain, be bent more often without breaking or cracking, and consequently hold a shoe upon the hoof longer than if not so annealed.

In the practice of my invention I place or pack the nail-blanks together as closely as possible, in, preferably, a wrought-iron retort, which is then covered and preferably hermeti- -cally sealed by clay or otherwise, so as to leave as little air as possible in the'retort. Then I place the said retort so filled with blanks in a furnace where the retort and its contents are raised to about a cherry-red heat, this usually requiring from eight to twelve hours, after which the retorts are removed from the furnace, and, yet closed, are, with their contents, permitted to cool slowly and gradually, such cooling requiring from ten to fourteen hours, according to the state of the surrounding atmosphere, the cooling preferably being done slowly.

The blanks punched from metal plates are more or less covered with oil, (for the plates are oiled before the blanks are, punched out,) and in such condition they are thrown into the retorts. The blanks are removed from the (N0 model.)

of low degree, to remove the dirt or the residuum of the oil left thereon after being heated, as described; after which they are tumbled, cold rolled or drawn, beveled to form finished points, and sheared, all in the usual way. In this my plan the retorts are made as cylinders about seven feet long by fifteen to twenty inches in diameter, and will hold from one to two thousand poundsof nail-blanks.

By keeping the oiled blanks in a sealed retort away from the air, I have found that they do not oxidize and scale is not formed on them, as in the old plan. I believe the oil left on the blanks lessens the tendency of the blanks to scale or oxidize, makes them softer and tougher, and leaves the blanks in such condition that they more readily takepolish and become bright by subsequent tumbling or rolling in the usual way.

I have in some of my experiments exhausted the air from the retort after filling it with blanks, and have heated the blanks in substantially a vacuum, and I have discovered that the more nearly the air is exhausted from the retort the lighter the color of the blanks, the softer the iron, and the less the scale.

The oil on the blanks materially assists in raising the heat within the retorts to a very high or intense degree, .as the oil being consumed is converted into gas. The dark residuum or coating left on the oiled blanks after they are cooled, as described, may be very easily removed by rattling or tumbling.

Forged nail-blanks may be annealed in the manner above described; but before placing them in the retorts I prefer to coat them with or dip them in oil. Figure 1 is a top or plan view, showing fnrnace containing three furnace-chambers, A B O, in a row. Furnace A contains one retort, and B three retorts, while the lid of the furnace-chamber O is engaged by the chain of the crane, which is to lift it and uncover said chamber. 1

Fig. 2 represents, in section, on the lineman,- Fig.1, afurnace-chamber, A, shown as containing but one sealed retort filled with nail-blanks, a crane being located near the furnace by which to remove or replace the retorts when desired.

Let it be supposed that A B 0 represent furnace-chambers of refractory material, and of usual construction, suitably connected by passage a with any'usual combustion'chamher or heat-generator, (not shown,) in which, by the consumption of coal or other fuel, heat may be generated to raise the temperature of the furnace-chambers, one or more, to a "ery high degree.

The furnace-chambers maybe of greater or less size, to contain one or more retorts, 0. Each furnace-chamber has a cover, I).

The retorts c consist of strong wrought-iron cylinders having bottoms inserted air-tight and provided with covers 0?, which may be fitted thereto and be sealed air-tight.

About the top of each retort I have shown a flange or projection, 2, to receive within it the head or cover (1, and preferably the flange 2 will be a little higher than the cover, to permit the joint or crack between the cover and flange to be sealed air-tight.

The cranc c, of usual construction, has a drum, f, and a chain, g, by which the cover b of the furnace-chamber and the retort may be moved or handled, as when placing the filled retorts into or removing them from the furnace-chambers.

When moving the retorts the flange atfords a ready means with which the usual hooks or chain of the crane may be engaged.

I claim That improvement in the method of manufacturing animal-shoe nails which consists in inclosing the oiled blanks, or blanks and oil,.

WILLIAM W. MINER.

Witnesses G. W. GREGORY, N. E. G. WHITNEY. 

